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5.
NON
PROCEDURE
PROTOCOL
COMMUNICATIONS
MELSEC QnA
5.6.4
Summary of data reception from external device using non
Drocedure Drotocol
The following uses an image diagram to outline data reception from an external device using the
non procedure protocol described in Section 5.6.3.
cpu
,@
Request to Read,
External device
@
End of Read
Monltor
GPPQ
@ When data is sent from the external device, the
QC24 stores the receive data to its buffer
memory (receive data storage area).
@ When the
QC24 receives the set end code
CR,
LF (ODOAH), it turns ON the *Request to Read
signal (X83) to the PC CPU.
@ The
PC CPU uses the sequence program to read the receive data from the QC24.
@
At the end of data read processing, the PC CPU turns ON the End of Read signal ("81).
When the End of Read signal ("81) is turned ON, the QC24 turns OFF the Request to Read
signal (X83) and completes one data communications.
*
: The INPUT instt
signals ON and
1
ON and OFF is
unnecessary.
lction automatically turns the QC24 Request to Read and End of Read
IFF by internal processing. A sequence program that turns these signals
PC CPU
QC24
External device
5 - 1 9
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